The Period of Fire Suppression and Other Fire Regimes (1890s to 1980s)

The fire suppression movement began in the late 1890s on the platform that fire destroyed destroyed forests and that excluding fire would conserve forests. The movement was led by Gifford Pinchot, the founder of the Forest Service, and supported by many foresters as well as timber, pulp, and paper companies. The new policy of fire control was developed partly in reaction to the environmental damages caused by industrial logging and the accompanying destructive wildfires. The United States Forest Service, under the command of Chief Forester Henry Graves, adopted fire control as a principle duty of the agency (Williams 2002). Fire suppression became the doctrine and leading policy of federal agencies. For instance, when the Great Smoky Mountains National Park was established in 1931, fire suppression was a central objective of forest managers (BROKEN-LINK Harmon 1982).

Throughout this period, there was opposition to fire suppression policies within federal and state agencies from advocates of “light burning” or “Indian fires” (Pyne 2000). The Forest Service experimented with “light burning” in the 1910s and concluded that prescribed fires were destructive (Williams 2002). In the 1924 Clark-McNary Act the federal government allocated funding for states to develop their capacity to fight forest fires (Stanturf and others 2002). In the 1940s, a federal fire prevention campaign was initiated, partly in response to several catastrophic forest fires in the Great Lakes Region caused by poor logging practices (Buckner 2000). Smokey Bear became the highly effective symbol of this campaign in 1944, teaching two to three generations of Americans that all fires are harmful to forests. Government officials who wanted to restore southern forests promoted the prevention and suppression of all forest fires and the restoration of desirable species (Williams 1998). Forest Service scientists examined the burning traditions and psychology of southerners to explain why 50% of fires annually in the United States occurred in 11 southern states (Shea 1940).

Prescribed burning was banned on many public lands in the South for more than 50 years. Federal policies were not successful in completely excluding fire from public lands; arson fires and lightning-ignited fires still occurred. On private lands – despite federal fire prevention policies – prescribed burning continued to be used by the farming, grazing, and logging industries and maintained its role in the southern economy.

Longer Fire Return Intervals

The era of fire prohibition that began in the early to mid 1900s caused a shift in fire regimes marked by longer fire return intervals. In the Great Smoky Mountains National Park, for example, fire return intervals increased from 10-40 years with a mean of 12.7 years during the Euro-American settlement period (1856-1940) to a 2000 year fire return interval in the fire suppression era (1940-1979). In the Ozark-Ouachita Highlands, the fire suppression era began in the 1930s. Subsequently, fire regimes changed drastically. In Hot Springs National Park the fire return interval in 1700 was 41.4 years, but by 1980 it had increased to 1200 years (Foti and others 1999). In McCurtain County Wilderness Area the fire return interval in 1700 was 29.9 years and in 1980 it was 547 years (Foti and others 1999).

Links Between Fire Suppression and Changes in Vegetation

The exclusion of fires from southern landscapes caused changes in vegetation. When fires became less common, forests began to re-grow or the composition of existing forests began to change.

In the Southern Appalachians, forests that were growing without the influence of fire included noticeably fewer pine species and more hardwood species. Thick understories of mountain laurel, rhododendron, and other shrubs developed in Southern Appalachian forests that previously had sparse understories. Fire exclusion resulted in the replacement of late-succession mesophytic species with more robust early succession species. In some parts of the Southern Appalachians, the regeneration of valuable hardwoods was an outcome of fire exclusion (Brose and others 2001). Other consequences of fire exclusion in the Southern Appalachians were the disappearance of grasslands (Kimmerer and Lake 2001), a decline in oak dominance, and development of thick understories of mountain laurel and rhododendron.

In the Missouri Ozarks, late-succession trees such as black oak and scarlet oak began replacing shortleaf pines, white oaks, and post oaks because fire was excluded (Foti and others 1999). In other parts of the Ozarks, oaks are becoming less dominant as maples, blackgums, and tulip-poplars replace them. On the prairies of the Ozark-Ouachita Highlands, prairie legumes and tall grasses are being replaced by eastern red cedar.

Fire regimes on the Coastal Plain of Florida have been mixed in past decades. This is evident on the Welaka Reserve in northeastern Florida and the Archbold Research Station in south-central Florida (Myers and White 1987) where the types of plants that are growing have different relationships to fire. Sand pine scrub, which favors infrequent, high-intensity fires, is a prominent vegetation type in both the Welaka and Archbold sites. Scrubby flatwoods, longleaf pine, and slash pine, which favor more frequent, lower-intensity fires, are also present. This is true even though prescribed fires were discontinued in the Welaka Reserve in 1935 and in Archbold Research Station in 1927 (Myers and White 1987). The relationships between the age and abundance of longleaf pines (older and less-abundant) and slash pines (younger and more abundant) suggest that fires became less frequent at these sites about 150-200 years ago (Myers and White 1987).

The decrease in Florida’s longleaf pine communities during the 20^th century was partly caused by the government’s ban on prescribed fire. The health of longleaf pine communities depends on frequent, low-intensity fires. Other causes for the decrease in longleaf pine densities are the logging and turpentine collecting that took place in the late 1800s and early 1900s. For these same reasons, several species of deciduous oak (Quercus laevis, Q. incana, Q. stellata, Q. falcata) have became more abundant in the former longleaf pine communities (Myers and White 1987).